15/04/2019

Antarctica Is Losing Ice At An Accelerating Rate. How Much Will Sea Levels Rise?

PBS NewsHour - William Brangham | Emily Carpeaux | Mike Fritz

The frozen continent of Antarctica contains the vast majority of all freshwater on Earth. Now that ice is melting at an accelerating rate, in part because of climate change. What does this transformation mean for coastal communities across the globe? William Brangham reports from Antarctica on the troubling trend of ice loss and how glaciers can serve as a climate record from the past.



TRANSCRIPT
  • Judy Woodruff:
    We continue now with our series from Antarctica.
    The ice-covered continent is being transformed in part by climate change. Antarctica's ice, which contains the vast majority of freshwater on Earth, is melting at an accelerating rate.
    William Brangham and producers Mike Fritz and Emily Carpeaux traveled there and have this report on how coastal communities all over the world could be impacted.
    It's part of our occasional series of reports, Peril and Promise: The Challenge of Climate Change.
  • William Brangham:
    For as far as the eye can see, Antarctica is covered by thick sheets of ice. In some places, that ice is several miles deep.
    This massive continent, as big as the U.S. and Mexico combined, has, for millions of years, been home to some of the most breathtaking landscapes of ice on the planet.
    What you can see behind me here is a very good cross-section of a glacier in Antarctica. And what you can see, with all those different layers that is hundreds and thousands of years of snowfall and precipitation stacking up, one on top of the other, and slowly exerting pressure downward on those layers of snow. And that's basically how a glacier is formed.
    But Antarctica's ice is now increasingly being threatened, and most researchers believe it's because of climate change. According to one recent study, the continent's ice is slipping away six times faster than it was 40 years ago.
  • Joseph  MacGregor:
    And Antarctica is now losing 252 gigatons of ice per year.
  • William Brangham:
    Glaciologist Joe MacGregor is part of the team at NASA's Goddard Space Flight Center that's studying Antarctica's ice.
    Using radar and lasers, they measure the thickness of the ice, how it's moving, and whether it's growing or shrinking.
    This animation they built shows a sped-up version of how the ice flows on the continent.
    Help me understand what that means, 252 gigatons.
  • Joseph  MacGregor:
    A gigaton is a billion metric tons of ice. And when you do the math, you wind up with the Antarctic ice sheet is out of balance by more than three-and-a-half swimming pools per second.
  • William Brangham:
    Every second, three Olympic-sized swimming pools worth of ice is disappearing from Antarctica?
  • Joseph  MacGregor:
    Yes, when considered on average over the year.
  • William Brangham:
    Just to put that in perspective, in the amount of time it takes to watch this story, Antarctica will shed more water than New York City uses every day.
    The warming that is causing this ice loss varies in different parts of the continent. Here on the peninsula, the long branch of land coming on the northwest corner of the continent, warming has been especially pronounced.
    At the Vernadsky research station, which is run by the Ukrainian government, meteorologists like Oleksandr Poluden have been keeping some of the longest-term temperature records on the continent. While it's warmed and cooled at different times, Poluden says the overall trend here on the peninsula is clear.
  • Oleksandr Poluden (through translator):
    You will notice that the temperature doesn't tend to increase all the time, as there are certain fluctuations from year to year. However, it becomes evident that, over about 70 years, the average year-round temperature has increased by 3.5 degrees.
  • Michael Oppenheimer:
    It's becoming clearer that parts of Antarctica appear to be unstable and are losing ice much faster than we expected.
  • William Brangham:
    Michael Oppenheimer is a climate scientist and professor of geoscience at Princeton University. He says this ice loss will only accelerate sea level rise, which happens for two reasons.
    One, a warming atmosphere warms the oceans, and warmer water expands and rises. Secondly, warming also melts ice and glaciers all over the world, sending new water into the ocean.
  • Michael Oppenheimer:
    So, ultimately, if we lose all the ice that's vulnerable to a warming of only a few degrees, we're talking about a very, very, very big sea level rise.
  • William Brangham:
    The most recent U.N. report predicts a foot of sea level rise this century if we continue burning oil and gas and coal at our current pace.
    But a growing number of researchers believe that, because of the emissions we have already put up into the atmosphere, that prediction understates the threat.
  • Alexandra Isern:
    the continent's warming from below and also, you know, from above.
  • William Brangham:
    Alexandra Isern oversees all Antarctic science for the National Science Foundation, who, for the record, is a "NewsHour" underwriter.
    She says that, in West Antarctica, two huge glaciers, Pine Island and Thwaites, are considered at serious risk of collapse.
  • Alexandra Isern:
    There's some researchers that study Pine Islands and the Thwaites Glacier that feel that it's become sufficiently destabilized that it won't — that we won't be able to recover.
  • William Brangham:
    Michael Oppenheimer says, if just one of those glaciers winds up in the ocean, sea levels will rise five times higher than the U.N. predicted.
  • Michael Oppenheimer:
    The current estimates are, if Thwaites Glacier were to totally disintegrate into the ocean, that, ultimately, sea level would rise by something like five feet.
    In areas around some of our biggest cities, New York, Boston, Miami, where you have got a lot of development, homes, buildings, infrastructure, like roads, very close to sea level, how do you defend those?
    How would Bangladesh protect itself? It's got many hundred of miles of coastline. It's all right at sea level. You can't build a wall to protect that whole coast. There's actually nothing that can be done.
  • William Brangham:
    That's millions of people that are going to have to move.
  • Michael Oppenheimer:
    Right. There are 150 million people that live in Bangladesh, and probably a few million of them would have to move back. Where are they going to go in such a densely populated country?
    And there's already strife when people try to move into India. People get killed trying to do that now. What's going to happen when you have a few million people that all of a sudden try to move? It's not a pretty picture.
  • William Brangham:
    Part of the reason Antarctica's glaciers are threatened is that they have been losing some crucial protection. Many glaciers form what are known as ice shelves, huge platforms of ice, some as wide as Texas and hundreds of stories tall, that grow out over the ocean and help hold their much larger glaciers up on land.
    They hold it back and not let it slide into the sea.
  • Robin Bell:
    Imagine a piece of ice the size of Texas. Pretty thick. It's going to slow the ice as it tries to flow into the ocean.
  • William Brangham:
    Robin Bell of Columbia University's Lamont-Doherty Earth Observatory has been studying Antarctica's ice for over 20 years.
  • Robin Bell:
    Ice shelves are very important. They are essentially acting as bouncers in the bar, leaning up against the door and keeping the ice from flowing into the ocean.
  • William Brangham:
    But as the atmosphere keeps warming, major ice shelves in Antarctica have also been collapsing. In 2002, the Larsen B Ice Shelf, the size of Rhode Island, completely disintegrated. These are satellite images of it breaking into hundreds of pieces.
    As predicted, the glaciers that Larsen B anchored up on land began accelerating towards the ocean. And then, two years ago, the even bigger Larsen C Shelf — this is it from the air — developed that miles-long crack in it. This shelf, which sits in front of the Thwaites Glacier, is also crumbling. And part of the Brunt Ice Shelf is expected to break off any day now, releasing an iceberg that'll be twice the size of Manhattan.
    There's still some debate over whether human-induced warming is the only thing causing these changes. Antarctica has lost ice many times before, and that also caused the seas to rise. Researchers are now trying to determine how much warmth it takes to cause truly catastrophic sea level rise.
    That massive glazer that you see behind me connects all the way up above those peaks to the enormous West Antarctic Ice Sheet. And all of that ice and snow contains a remarkable history of Earth's past climate.
  • Alexandra Isern:
    It's like a tape recorder, a 10,000-foot tape recorder in places. And so scientists have drilled ice cores through the layers as far down as they can get, and then they analyze those layers.
  • William Brangham:
    Glaciologist Robert Mulvaney — that's him in the black cap — works for the British Antarctic Survey. He and a small team have been drilling over 2,000 feet down into the ice sheet, and pulling out these ice cores.
  • Robert Mulvaney:
    What we have been trying to do is recover a climate record over the last glacial cycle, so the last 120,000 to 140,000 years, to try to understand how our climate might change over the next hundred years or so, as we — as the climate responds to increased carbon dioxide in the atmosphere.
  • William Brangham:
    The evidence from these cores and many others indicate that when the Earth's climate was just a little bit warmer than it is today, the world's oceans were over twenty feet higher.
  • Robert Mulvaney:
    So, 120,000 years ago, when the climate was probably two degrees warmer than today, the sea level was maybe six to nine meters higher than today.
  • William Brangham:
    Given the uncertainties over how serious sea level rise will be, and over what time span it'll occur, Michael Oppenheimer argues that there's still time to act and to prepare.
  • Michael Oppenheimer:
    It doesn't mean we should all throw up our hands and run.
    Let's start thinking straight, let's start thinking fast about how we're going to help people, how we're going to help settlements, how we're going to help countries deal with the outcome, because a lot of it is not going to be pretty. It's going to be expensive, and it's going to be disruptive, if we don't get our act together now.
  • William Brangham:
    This year, teams from several different nations are studying the Thwaites Glacier, trying to determine whether it's past the point of no return, and, if so, how soon its ice could end up in the ocean.
    For the "PBS NewsHour," I'm William Brangham in Antarctica.
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What Survival Looks Like After The Oceans Rise

New York Times - Photographs Andrea Frazzetta

At the site of a Bangladeshi town lost to devastating storms, locals make do by scavenging what remains.
Hunting for bricks on the flooded coastline of Bangladesh. Andrea Frazzetta/Institute, for The New York Times
Standing sometimes waist-deep in seawater on the shores of the Bay of Bengal in Bangladesh, they work to find bricks, dig them out of the sludge and cart them to the side of the road to sell. The job is new, a result of devastating storm surges a little more than a decade ago. In 2007, and then again in 2009, cyclones battered the coastline just south of Kuakata, destroying homes and structures and drowning entire villages. The storms submerged forests of mangroves and left 99 local residents dead.
The sisters Kulsum and Komola Begum survived. Now they scavenge, looking for debris. They wait until low tide, when the receding waves reveal the rubble. Once they’ve wheeled bricks to the embankment, they break them into small, chestnut-size pieces. These shards are used in the foundations for homes in the new village, a mile up the shore.
Despite being responsible for only 0.3 percent of the emissions that cause global warming, Bangladesh is near the top of the Global Climate Risk Index, a ranking of 183 countries and territories most vulnerable to climate change. When scientists and researchers predict how global warming will affect populations, they usually use 20- and 50-year trajectories. For Bangladesh, the effects of climate change are happening now. Cyclones are growing stronger as temperatures rise and are occurring with more frequency.
Researchers warn that within a few decades, Bangladesh may lose more than 10 percent of its land to sea-level rise, displacing as many as 18 million people. Decisions to leave coastal communities aren’t really decisions at all. Families leave because there are no other options. There is no work. There are no homes. Over the past decade, an average of 700,000 Bangladeshis a year migrated because of natural disasters, moving to Dhaka to live in sprawling slums as climate refugees. Kulsum and Komola have managed to forge opportunity from disaster; they will stay, for now. They will continue to collect bricks to build the new village, even if the new village will most likely meet the same fate as the old one. — Jaime Lowe
A gathering at Komola Begum’s home, from left: Her father, Abdul Latif Howlader; Komola; her son Nur-un-Nabi; her sister Kulsum Begum; and a neighbor. Andrea Frazzetta/Institute, for The New York Times
 Making a Living in the Ruins
The sisters Kulsum and Komola Begum make a living scavenging bricks, which they sell to construction workers for roughly $1.40 a sack.
During monsoon season, when currents are stronger and tides wash away the sand, the family can bag 60 to 70 sacks. Over all, they earn enough to send the children to school and buy uniforms and books.
A neighbor. Andrea Frazzetta/Institute, for The New York Times
Kulsum Begum and her granddaughter Marium. Andrea Frazzetta/Institute, for The New York Times
Komola Begum’s sons sometimes help their mother collect the bricks. “When I can earn, my children can eat. If I don’t, they will starve,” Komola said. “I do this for my kids.”
Nur-un-Nabi and Bellal Nabi. Andrea Frazzetta/Institute, for The New York Times
Her son Nur-un-Nabi plays outside his family’s home, which is surrounded by fields of rice and grasses. When he is not at school, and not helping his mother on the shore, Nur-un-Nabi can often be found running on thin slippery dams, occasionally chasing a water snake slithering out of the flooded rice fields.
Andrea Frazzetta/Institute, for The New York Times
The dozen miles of beach crowns the tourist town of Kuakata, roughly two hundred miles south of Dhaka. The beach is surrounded by forests of mangroves and palm plantations, which are falling victim to increasingly aggressive cyclones, tidal surges and rising seas. ‘‘When we were young, the old people used to say that the sea was very far from here,’’ Komola said. ‘‘They packed up their meals and walked their way to the sea. But now you can reach it in no time.’’
Andrea Frazzetta/Institute, for The New York Times
Komola Begum loads bricks onto a cart that her son Bellal Nabi will pedal a few hundred yards along a path of hard-beaten earth up to an embankment where the bricks will be unloaded and broken into smaller chunks.
Andrea Frazzetta/Institute, for The New York Times
Nur-un-Nabi breaks bricks, while his aunt Kulsum does the same a short distance away. The piles of bricks rest on an embankment that was recently raised to make it more resistant to cyclones. The Begum families’ homes are about a hundred yards from the embankment — which the more pessimistic local residents expect will withstand just a few more cyclones before being washed away.
Andrea Frazzetta/Institute, for The New York Times
Komola and Kulsum Begum load a bag of brick for a client. A bag can be as heavy as 40 kilos, and the two sisters often help each other with the task. “It is a good business so far,” Komola said. “Sometimes we get pre-orders, and this is good money.”
Andrea Frazzetta/Institute, for The New York Times
At each low tide, new scraps of bricks are revealed in the mud. A few decades ago, Komola Begum recalled, there were fishing villages here, and roads, rice fields and plantations.
“Some bricks come from the fishing nets,” where they are used as weights, she said. “We don’t know where the others come from.” She assumes that many come from homes that have been swept away. “Now everything is under the sea,” she said from the beach, pointing toward the ocean.
Andrea Frazzetta/Institute, for The New York Times
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Radical Climate Action 'Critical' To Great Barrier Reef's Survival, Government Body Says

Fairfax - Nicole Hasham

Australia’s top Great Barrier Reef officials warn the natural wonder will virtually collapse if the planet becomes 1.5 degrees hotter – a threshold that scientists say requires shutting down coal within three decades.
This federal election campaign is a potential tipping point for Australia’s direction on climate action, as the major parties pledge distinctly different ambitions for cutting greenhouse gas emissions.
However neither party has rejected the proposed Adani mine outright or promised to phase out coal, an export on which Australia is heavily reliant.
The Great Barrier Reef Marine Park Authority says limiting global warming to 1.5 degrees is "critical".
Climate change has already wrought devastating effects on the World Heritage-listed Great Barrier Reef, including two consecutive years of mass coral bleaching in 2016 and 2017.
In response to the threat, the Great Barrier Reef Marine Park Authority – the federal government’s lead agency for managing the reef – has prepared a climate change position statement.
The document, obtained by the Sydney Morning Herald and The Age under freedom of information laws, has not been released to the general public despite being in development for the past 15 months.
It states that limiting the average global temperature increase to 1.5 degrees or below since industrial times began – the higher end of the Paris agreement target - “is critical to maintain the ecological function of the Great Barrier Reef”. The world has already warmed by 1 degree.
Ecological function refers to roles performed by the reef's plants, animals and habitats, including providing a tourist experience. The authority has said these processes are necessary for the reef to exist.
The document cites scientific evidence that the reef could experience temperature-induced bleaching events twice per decade by about 2020 and annually by 2050 under high-emissions scenarios.
The IPCC says the global coal industry must virtually shut down by 2030 to prevent catastrophic climate change. Credit: Fairfax Media
The authority has long said climate change is the greatest threat facing the reef. However climate action advocates say to date, it has not sufficiently emphasised the repercussions of exceeding a 1.5-degree temperature rise.
A report prepared by the United Nations' Intergovernmental Panel on Climate Change in October last year said it was possible to keep warming below 1.5 degrees, but only with "rapid, far-reaching and unprecedented changes in all aspects of society".
This included phasing out coal-generated electricity globally by 2050, unless unproven technology to capture carbon dioxide from coal plants was deployed.
The Morrison government has pledged to cut Australia’s emissions by 26 per cent by 2030, based on 2005 levels. Experts say the target is not in line with keeping global warming below even 2 degrees.
The government has been plagued by internal divisions over emissions and insists coal has a strong future in Australia.
It has backed the controversial Adani mine and is considering underwriting new coal-fired generation projects in a bid to boost energy reliability and affordability.
By 2030, Labor wants half of Australia’s electricity needs met from renewable sources and a 45 per cent cut to national emissions. It says a transition away from coal is inevitable, but has no plans to shut down the industry. It has expressed scepticism about the Adani mine's future but has not pledged to stop it if Labor wins government.
The Greens say that by 2030, thermal coal exports and coal burning in Australia should cease.
WWF-Australia head of oceans Richard Leck said the reef authority’s explicit recognition of the need to stay below 1.5 degrees of warming was a “long time coming”.
“Now [a government agency] has made it absolutely clear that we need a climate policy that is consistent with 1.5 degrees or lower. We absolutely need to see that backed up by substance,” he said.
Fish swim among bleached coral in the Great Barrier Reef. Credit: Ove Hoegh-Guldberg
University of Queensland marine scientist Ove Hoegh-Guldberg, a lead author on IPCC reports, said the Morrison government was displaying “cognitive dissonance” by signing the Paris treaty but not taking strong climate action.
“You can’t have the Great Barrier Reef and the Adani mine, and what that [mine] represents in terms of future resource extraction. It is simply a big contradiction.”
Professor Hoegh-Guldberg said Labor’s 45 per cent target aligned “with the very best science coming from the international community”.
Labor’s climate change and energy spokesman, Mark Butler, said the party “agrees that climate change poses a severe risk to the Great Barrier Reef and real action is long overdue”.
A spokesman for Environment Minister Melissa Price said limiting climate change was important for the reef but it was "a global problem requiring a global solution, and Australia is playing its part".
He cited the Coalition's $3.5 billion carbon solutions package and commitment to the Paris treaty and the $443.3 million grant to the Great Barrier Reef Foundation to improve the reef's health.

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